Infection is prevalent and often the ultimate cause of death among hospice patients. However, there are currently no guidelines for antimicrobial use in hospice care; nor is it clear where antimicrobial therapy fits in the hospice treatment paradigm which primarily focuses on symptom management and quality of life rather than curative therapy. This high burden of infection and lack of guidance has resulted in a prevalence of antimicrobial use estimated between 40-50% over the duration of hospice care. Critical to decisions on whether or not to use antimicrobial therapy in hospice care is an understanding of the benefits and harms of antimicrobial use in this population. Treatment decisions must incorporate both the potential beneficial effects of antimicrobial use (e.g. reducing infection- associated symptoms) and the potential negative effects including adverse events (e.g. antibiotic- associated Clostridium difficile infection). However, at present there are limited data on clinical benefits and no data on the incidence of antimicrobial therapy-associated harms in hospice care. In this application, we propose a retrospective pharmacovigilance study to collect pilot data on the benefits and harms of antimicrobial therapy in hospice care. These data will provide an evidence base on which future prospective pharmacovigilance studies can be effectively executed. To accomplish these objectives, we will perform a retrospective chart review of hospice decedents who received antimicrobial therapy during their hospice stay. We will use data extracted from patient charts to estimate both the clinical benefit of antimicrobial use and associated harms using the Edmonton Symptom Assessment System, the National Cancer Institute's Common Terminology Criteria and adapted Naranjo criteria for attribution of harms to therapy. In addition, we will validate data extracted from the charts using cross-sectional data collected during Interdisciplinary Group meetings. The expected outcomes of this study are the first patient safety data on antimicrobial use in hospice care upon which future prospective multi-site pharmacovigilance studies can be based.